Nature 348, 342 - 344 (22 November 1990); doi:10.1038/348342a0

Induction of RNA-stabilized DMA conformers by transcription of an immunoglobulin switch region

Mary E. Reaban^* & Johanna A. Griffin^†

^*Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
^†Department of Molecular Biology, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut 06877, USA

A DELETIONAL DNA rearrangement is associated with immunoglobulin class switching from IgM to IgG, IgA or IgE (reviewed in ref. 1). This recombination occurs in immunoglobulin switch regions, which are complex, highly repetitive regions of DNA. As switch regions become transcriptionally active^2,3 just before switch recombination, analysis of the behaviour of these sequences during transcription could elucidate the mechanism of switch recombination. Here, we report that transcription of a supercoiled plasmid containing the murine IgA switch region (S)leads to a loss of superhelical turns. The resulting series of less supercoiled plasmids is stabilized by RNA-DNA hybrids formed by the nascent RNA transcripts, which remain base-paired with their DNA templates.

References

1.	Lutzker, S. G. & Alt, F. W. in Mobile DNA (eds Howe, M. M. & Berg, D. E.) (American Society for Microbiology, Washington DC, 1989).
2.	Stavnezer, J. et al. Proc. natn. Acad. Sci. U.S.A. 85, 7704−7708 (1988). | ChemPort |
3.	Lutzker, S., Rothman, P., Pollock, R., Coffman, R. & Alt, F. W. Cell 53, 177−184 (1988). | Article | PubMed | ISI | ChemPort |
4.	Stanton, L. W. & Marcu, K. B. Nucleic Acids Res. 10, 5993−6006 (1982). | PubMed | ISI | ChemPort |
5.	Liu, L. F. & Wang, J. C. Proc. natn. Acad. Sci. U.S.A. 84, 7024−7027 (1987). | ChemPort |
6.	Tsao, Y.-P., Wu, H.-Y. & Liu, L. F. Cell 56, 111−118 (1989). | Article | PubMed | ISI | ChemPort |
7.	Wu, H.-Y., Shyy, S., Wang, J. C. & Liu, L. F. Cell 53, 433−440 (1988). | Article | PubMed | ISI | ChemPort |
8.	Giaever, G. N. & Wang, J. C. Cell 55, 849−856 (1988). | Article | PubMed | ISI | ChemPort |
9.	Collier, D. A., Griffin, J. A. & Wells, R. D. J. biol. Chem. 263; 7397−7405 (1988). | PubMed | ChemPort |
10.	Radcliffe, G., Lin, Y.-C., Julius, M., Marcu, K. B. & Stavnezer, J. Molec. cell. Biol. 10, 382−386 (1990). | PubMed | ChemPort |
11.	Htun, H. & Dahlberg, J. E. Science 243, 1571−1576 (1989). | PubMed | ISI | ChemPort |